As far as i've understood, you get 1 token from bosses(in this case i'm talking about Frumious Fang from Snarbolax "Shadow of the Beast" run) depending on how many levels your were part of, up to and including the boss battle itself.
In this case, you should get a total of 3 Frumious Fangs from a solo-snarbolax-run.
I did 2 runs today(intend to do another later today as it seems to be the most crowns-rewarding for me currently, if anyone have got a tip of earning crowns faster i'm listening)
First run: 3 Tokens, nothing weird